Freelance M_ANA Hyst
Does anyone know how to calculate de Hysterisis value for a H or L alarm?
Is it in percentage of the range? Because I have test it and it seems to me that the Hyst value is a % on the alarm setpoint. Is this correct? How can I do to have the same hysterisis value in all the allarms? For example 1% of the meassuring range.
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Yes you are right.
The Hyst value is % of the alarm setpoint.
The problem is for example an alarm value from zero will have no hysterese :-(
if you want the messuring range as basis for the hyst, you have to calculate
every alarm hyst.
For example range 0-100%; alarm 25 %
Hyst 1% of range = 100/25 * 1% = 4% Hyst
the Hyst. setting is in percentage of the limit value, not the measuring range.
If your measuing range is from 0..200 and the limit is 150, then a Hyst of 0.1 means a hysteresis of 15, which means the value has to go back below 135 in order to show the alarm as gone and create a new alarm once it reaches 150 again.
If you want 0.1 for every hyst. value in an M_ANA you could either use the Bulk-Data manager, or keep a properly configured M_ANA in a program in the pool and copy it from there whenever you need one.